1897 THE MICROSCOPE. 155 
PRACTICAL SUGGESTIONS, 
By L. A. WILLSON, 
CLEVELAND, OHIO. 
Water Sediment.—Use no stain or reagent of any kind 
if it be desired to see the contents alive or in a natural 
condition. Ifthe water appears clear to the unassisted 
eye, nothing will generally be seen with the glass unless 
it be stained or allowed to settle and the sediment examined. 
To examine water from hydrants tie a bag over the spigot 
and let it run until the bag swellsup likea sausage. Then 
remove the bag, turn the water into a conical glass, wash 
the sediment adhearing to the sides of the bag into the 
glass and set itaway tosettle. Nearly always, little specks 
will be found onthe surface that prove interesting and 
which should be first viewed with aninch objective. The 
settling at the bottom should be examined thus: Dip a hol- 
low tube, while holding a finger over the top. When the 
bottom is reached, remove the finger and let the sediment 
runupthetube. Then again close the top with the finger 
and let the drop fall upon a glass slip. Then cover and 
examine, first with aninch, and after with a quarter inch 
or higher objective. A bag in which smoking tobacco is 
sold, when thoroughly washed before using, will be found 
to be one of the best bags that can be used for the purpose. 
Focussing.—It is avery safe and proper procedure in 
using powers Of a quarter inch and higher, to carefully 
bring the objective down to the cover and then focus up- 
wards with the coarse adjustment and, when almost ob- 
tained, finish with the fine adjustment. 
Mounting Insects.—Small and nearly transparent in- 
sects may te prepared for mounting in Canada Balsam by 
soaking fora short time in oil of cloves or turpentine. 
Larger and darker insects must be rendered transparent. 
They should be soaked for twelve hoursin a weak solu- 
tion of caustic potash. The soft portion should then be 
carefnlly brushed off with a camel’s-hair pencil. This 
latter process should be accomplished by placing the slip, 
